How to change the timescale of a signal?

I was wondering how one would change the time-scale of a signal. In particular I have a stimulus that changes every 0.62 ms or so, and either has a value of +1 or -1. I need it so that I have the value of the stimulus at each ms. I have tried various re-sampling/up-sampling functions but I have had limited success so far. Thanks.

Answer 1

[Fangjun Jiang]

resample() can be used sometimes. But since your signal value is either +1 or -1, I guess you might want to resample it using the last known value.

%%Original data
t=0.62*(0:9);
y=round(rand(10,1))*2-1;
figure(1);
stairs(t,y);
ylim([-1.5 1.5]);

% New data
T=0:0.001:t(end);
ind=bsxfun(@le,t',T);
Y=y(sum(ind));
figure(2);
plot(T,Y,'r+');
ylim([-1.5 1.5]);